


Red Flags

by 0neType



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Blackmail, Coercion, Emotional/Psychological Abuse, Forced Incest, Forced Prostitution, M/M, Rape/Non-con - Freeform, Red City AU, Sexual Abuse, Suicidal Thoughts, meant to be read by absolute monstrous garbage only, no jokes guys this is pretty awful
Language: English
Status: Completed
Published: 2016-10-25
Updated: 2016-10-25
Packaged: 2018-08-24 13:38:07
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 1
Words: 8,260
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8374159
Author URL: https://archiveofourown.org/users/0neType/pseuds/0neType
Summary: Sans is forced to work as a prostitute for Muffet with no way out of the arrangement. His latest client is a shapeshifter that perfectly mimics monsters that Sans knows. When the client ends up turning into Papyrus, things get particularly awful.





	

**Author's Note:**

  * For [Germindis](https://archiveofourown.org/users/Germindis/gifts).
  * Inspired by [Red Light District](https://archiveofourown.org/works/6782854) by [Germindis](https://archiveofourown.org/users/Germindis/pseuds/Germindis). 



> This fic continues off of Chapter 6 of Germ's fic Red Light District. It starts and ends directly with bits of the original chapter so if you've read the fic, you'll probably recognise it. ( ͡° ͜ʖ ͡°) If you _haven't_ read the fic (or series), pleaseeeee do, cuz it's so damn good.
> 
> Unless, of course, you're a wholesome sort of person, in which case, dear lord, don't read this fic either because it is... Not A Fun Time.
> 
> If you want to read this anyway and don't know a thing about RLD, this is all you need to know:  
> \- Sans is an unwilling prostitute for Muffet  
> \- Papyrus has no idea Sans has this job and Sans CANNOT let him find out  
> \- The pudding is an aphrodisiac  
> \- Tuna is Sans' the designation Muffet gave him for the type of worker he is  
> \- Sans was having an almost okay time with the shapeshifter till it decided to turn into his bro

“I've got one more I want to do.”

The monster got up and slid off the bed. He walked toward the wall.

“Come over here.”

Sans hopped off the bed and started to follow, but got an uneasy feeling he couldn't explain to himself as the other monster leaned back against the wall. Sans' arousal was inexplicably dissipating into nothing, being replaced by a quiet anxiety.

The monster put on a show of making a decision. It spoke quietly, barely above a whisper, but Sans heard every word.

“I wonder how dirty you really are?”

And when Sans caught the look in the monster's eye, somehow he knew.

“How about you call me...”

“No. Don't. Don't you dare, don't you fucking dare—”

“Boss.”

A perfect copy of Papyrus stood in the shadows.

Sans stumbled backwards. The Papyrus copy didn't follow. It stood regally upright against the wall. Sans fell to the floor and scooted himself further away with rapidly kicking feet.

“Come here, Sans.”

Sans froze. Something about the phrase had been drilled very effectively into him. But Onion's training lost an internal battle against deep revulsion. Sans stayed where he was, and the Papyrus copy did too. That look it was giving him—it was psyching him out, wanted to break his spirit by getting him to come to him on his own—

Or maybe not. Sans caught the flash of a lens in the corner above the monster. Did it know the camera was there? Was it against the wall on purpose? Did it know it happened to be in the best blind spot in the room? That couldn't be a coincidence, could it?

But why would it...unless it was doing something it wasn't supposed to. Muffet had let Sans endure a number of horrors already without stepping in once, but maybe this was finally something she wouldn't allow. If she knew it was happening.

Sans remembered the monster in the monitoring room, toggling the sound of the different displays. Had they heard the monster use Papyrus' voice, or had they missed it? Was he speaking too softly? They needed to get the visual.

Sans just had to stay over here in the middle of the room, where nothing could hide from the cameras, and wait. Either the monster would be drawn out and his game would be up, or he would give up and do something less utterly despicable. Sans looked at the door.

A shadow fell over him.

“That’s not going to do you any good, dear brother.”

Sans felt a cold wash of horror flood through him as a firm hand came down to grip at his shoulder, phalanges disturbingly familiar in their weight. Fear froze him in place, unable to even move his head to turn back around to look at the monster wearing his brother’s face. He heard a chuckle from behind him and he was struck by an image from what seemed like ages ago, watching movies with Papyrus on their couch, passing comments that made his brother groan in frustration, reveling in the sense of accomplishment when one finally,  _ finally _ , won him a startled laugh—

“Please,” he croaked, and the monster shifted into view in front of him, crouching down till he was at eye-level. Sans immediately looked down, body starting to tremble even just at the sight of polished red boots, “Please. P-please don’t. I c-can’t. I  _ can’t _ .”

The monster was in full view of the camera now but there was no sign of Muffet or any guards. Was she on her way? Would she stop this? Or had the monster standing in the blind spot just been a coincidence? He certainly seemed unconcerned right now, center stage and in full view.

Sans risked another glance up at the camera.

“Sans, stop that.” The copy scolded lightly and the tone was so perfectly Papyrus that Sans could feel the automatic apology forming at his teeth. But there was the edge of something teasing in it, an undertone he’d never heard his brother use before, and that was just enough to hold the words back. He continued to stare up at the camera, desperately hoping that, of all things, Muffet would at least spare him  _ this _ .

A sigh.

The monster shifted forward and scooped Sans up into his arms.

“No,” Sans gasped and started to kick, the instinctive need to escape rushing in as the monster pulled him up close to his chest, “No, no, no—don’t—I won’t—Muffet won’t let you!”

He tried fiercely not to think too close about the practiced feel of being in his arms, tried not to compare it to the hazy, drunken memories of being carried upstairs to his room on nights when he’d come back loose-limbed and swaying from Grillby’s. Or worse still, of being carried after the encounter on rotten egg street, clinging to his brother for safety and protection after the slug had—

He kicked harder, wanting more than anything to put as much distance between the two of them that he could. Unfortunately, his continued struggling only prompted the monster to grip onto him tighter, gloved claws biting into him and making Sans wince. He still refused to look at the copy—couldn’t meet his gaze head on when he knew what he’d be seeing.

“I think you’re forgetting who I am.” Sans shook his head. He wasn’t the Boss. He wasn’t Papyrus. He  _ wasn’t _ . “My position in the Royal Guard gives me the benefit of holding power over a lot of weaker monsters, Sans. Getting a few guards to turn a blind eye isn’t that difficult a task.”

The monster tossed him down onto the bed and Sans bounced lightly on it once before quickly scrambling up and instinctively reaching for his magic. A sick lurching in his soul reminded him that it was still well out of reach, the tracker still embedded deep within his core. A swell of panic overwhelmed him at the thought and his fingers shook even as he clumsily pushed a hand into his ribcage to reach for his soul. He’d have to pull it out, he’d have to dig in and rip it out of himself and, if he couldn’t, he’d just crush his soul within his own palm because it would still be better than this— _ anything _ would be better than this—

Two hands wrapped tightly onto his wrists, wrenching them immediately away from his ribcage. The shock of it made Sans gasp aloud, phalanges twitching still in the phantom search for his soul. A frigid chill coursed through him as the shapeshifter slowly crawled closer towards him, the black of Papyrus’s copied outfit more vivid than it had any right to be as it filled up Sans’ field of view.

“You ought to be more careful, brother. You could get hurt like that.”

“Fuck you,” Sans snarled, yanking at his captured wrists and twisting in the sheets. He’d rip his arms out of his sockets if it meant a chance at getting away. He wouldn’t let this happen. He  _ wouldn’t _ . He’d die if it came down to it but he wouldn’t let this monster use his brother’s face and debase him like this.

“ _ Sans _ .” The monster sighed and the admonishment in his voice was so nostalgic that Sans’ soul skipped a beat at the sound.

He was going to be sick.

“G-get off me! Get off of me, you fucker!” He spat, pushing back the nausea and gathering all the vile resentment building inside him into a heated struggle, “You’re not him! Fuck you, you’re not—”

He was silenced by the press of a wet kiss to his mouth, a tongue slipping easily in between his parted teeth. He was too shocked to do anything but freeze stiffly as the monster licked into him, fingers prying into the space between his jaws to keep him from biting down. His soul churned uncomfortably but fear kept him locked in place.

The Papyrus copy pulled back and Sans truly looked up at him at last, head feeling heavy and body shaking. Sharp cheekbones, scarred socket, pointed teeth; not a single feature out of place. A face as mock-angry and long-suffering as Sans remembered it, despite the smug expression currently adorning it. Everything down to the slightly crooked ridge of Papyrus’s nasal bone—it had healed wrong. Papyrus had broken it when they were just kids. His brother had fallen flat on his face while chasing after Sans in anger over some prank or another. Sans remembered laughing—was absolutely identical.

He felt the tears spring to his sockets, “You can’t—y-you can’t  _ do _ this to me.”

It was as if the fight had been drained out of him, his emotions leaving him weak and trembling and completely out of sorts. The monster climbed over him, pushing him softly into the mattress. Sans couldn’t find it in himself to offer even token resistance. Tears continued to drip steadily down his face as the shapeshifter pinned his wrists down to either side of his head, boxing Sans in underneath him.

Papyrus’s scarf dangled over his face, tickled where it brushed against him.

Sans shuddered.

“S-stop. Please. You—you can be anyone.  _ Anyone _ . J-just—just not  _ him _ . Please, I… I-I’ll do  _ a-anything. _ ”

“Hmm, that’s quite a thing to say.” It was almost a relief to hear the monster’s natural voice spring from between Papyrus’s teeth, all reedy and high-pitched, “I had a back-up option in mind but… can you really be sure that you’ll like that any better?”

He couldn’t.

There was no form the monster could  _ possibly _ take that Sans would ‘ _ like _ ’ any better. He could only ever hate it a little less. But, between being raped by someone he knew and talked to from time to time and being raped by his  _ brother _ —

… Sans would take what he could get.

The monster leaned further down over him, let the tongue uncurl from Papyrus’s mouth and licked a long, wet stripe along the side of his neck where the hood of his jacket didn’t obstruct it. The monster stayed there for a moment, grazing his brother’s teeth against the notches of his vertebrae teasingly. The full-bodied shudder of revulsion that followed only made the monster chuckle again, forcing Sans to bite back a noise of distress at how its voice had switched back into Papyrus’s familiar cadence.

“I suppose it doesn’t matter,” the shifter said as it pulled back up again, “Since I’m enjoying your reactions far too much to consider changing in the first place.”

Sans felt his soul sink deep, a black void of horror enveloping it entirely, “No, no, no. No, please, I—”

“Shhh,” the monster soothed, a red-gloved hand coming up to stroke his face.

At the contact, tears sprang afresh in his sockets. The monster huffed out a breathy laugh at the sight of them. It drew out its conjured tongue once more and Sans squeezed his sockets shut, not wanting to see the red glow come any closer. His tears spilled over at the action and the shifter drank them up, leaving crawling sensations in his bones in the wake of its attention.

It brushed a hand down towards the hem of his shirt, lifting just enough to expose his spine.

“Oh g-god, oh fuck, p-please… please don’t.”

Sans felt like he was choking on his pleas and his own rising nausea. But the monster ignored him, happy to indulge in its continued exploration of his body. Its hand slid underneath the ratty, red t-shirt he wore, reaching for his spine. Papyrus’s copied fingers curved into the dips between each vertebra as they travelled teasingly up and down. Try as he might, Sans couldn’t distract himself from the feeling, each caress wrenching another wretched sob from him till he was shaking and begging for mercy with every breath.

“Please stop, please stop, p-please…stop, please…”

Despite the fact that he was still mostly dressed, he felt completely stripped naked. What good were an old shirt and a tattered jacket when his pelvis was bare and he was pinned to a mattress, waiting to be fucked? He was powerless; no magic to speak of and no way to escape this living nightmare. Even if he attempted to fight further, it’d be pointless. With his luck, the monster would likely hold him down and take him anyway; wouldn’t even dust him afterwards to spare him the horrors.

Still, as the monster used Papyrus’s hands to stroke at the crests of his hips, Sans couldn’t stop the instinctive fear that gripped him and screamed at him to act.

He lashed out with a rough kick, the retaliation unexpected enough to actually catch the monster solidly in the chest, “ _ No…! _ No, no, no! G-god,  _ fuck _ , I—”

But the struggle was short-lived—Papyrus’s armour didn’t leave room for any lasting physical damage and, once the surprise wore off, the monster grabbed onto his flailing legs with ease.

“ _ Enough _ ,” the shifter growled, Papyrus’s eyes narrowing at him as it twisted the offending leg sideways.

Sans yelped at the pain that shot up through the bone and felt his HP slide down incrementally. Its grip tightened further, enough that Sans could hear the leather of Papyrus’s gloves creak and his own bones start to groan in protest. Sans didn’t want to obey, but the sudden burst of energy had been ripped right out of him with one brutal wrench of his leg. Instead, his body continued trembling, hiccoughing sobs escaping him at the slightest movement from the monster above him.

The monster continued to keep him trapped, one hand pressed firmly to his chest to keep him down while the other felt around at his side. If Sans still had it in him to be anything other than mind numbingly terrified, he might’ve been curious as to see what it was doing. As it was, the stern gaze periodically peering down at him from Papyrus’s face kept his limbs too locked up to react. So, when the monster wearing his brother’s body finally found what it was looking for and turned back towards him, Sans could do nothing but stare in horror at the glinting silver spoon in its hand.

“Open wide, dear brother.”

This was really happening.

“I promise you’ll feel much more relaxed after this.”

This was  _ really happening. _

The monster brought the spoonful of pudding up to his mouth.

Sans  _ screamed _ .

“NO!  **_NO!_ ** FUCK YOU! LET ME  _ GO _ YOU FUCKING FREAK!”

It was one thing to be forced to endure this torture and another thing entirely to be forced to  _ enjoy _ it. To make him want it—to make him  _ complicit _ in this abomination—

No.

**_No_ ** .

As Sans began to struggle, the monster let the full weight of Papyrus’s body drop down onto him to keep him restrained. It easily pinned both his wrists back with one of Papyrus’s much larger hands and, with the other, calmly inched the spoon towards his mouth. All Sans could do was strain his head back as far as he could away from the drug.

“YOU’RE  _ SICK _ ! YOU’RE FUCKING  _ DISGUSTING _ !”

Maybe if he was loud enough, someone would hear him and know something was wrong.

“I HOPE YOU  _ BURN! _ ”

Maybe Muffet would be pass by and wonder just why her tuna was suddenly so active that he was yelling loud enough to bring the walls down around him.

“I HOPE I’M AROUND TO SPIT IN YOUR  _ DUST! _ FUCK YOU!  **_FUCK YOU!_ ** ”

Maybe, maybe—

The monster let go off his wrists and slapped him, sharp and firm, across the face.

The shock of it made him cry out, pain spreading like a pulse from the point of impact even as his HP took another dip. The shapeshifter used his moment of disorientation to push the spoon into his mouth and spill its contents onto his tongue. Quicker than Sans could react, it recaptured his wrists with one hand and clamped the other over his mouth to keep him from spitting the drug out.

Sans struggled against the hold but the monster held on tight, challenging every angry buck from Sans with a calm, impenetrable stoniness. Desperate, Sans tried to smear as much of the pudding as he could onto the glove sealed over his mouth but, already, he could feel it start to dissolve on his tongue. Panic was settling into him, along with a creeping warmth suffusing into his bones.

He could feel the tears spring back to his eyes.

The Papyrus copy grinned at the sight of it, “You  _ owe _ me this, brother.”

Sans tried to focus on the words instead of the way his magic was starting to strain against his restraint in an effort to form, “W-what… what a-are you…?”

“Just think about it,” Not-Papyrus said, letting his eyes drink in the sight of Sans’ body going flushed underneath him, his efforts not enough to keep the drug from doing its job, “Do you have  _ any idea _ how much of my time I’ve spent chasing after you? Over and over again, no matter how many times you got kidnapped on a whim?”

It wasn’t Papyrus saying this— _ it wasn’t him. _ But.

The words stung all the same.

Sans knew it was true—he’d regretted the fact enough on his own by now—but, for the shifter to bring it up with such confidence… like he really  _ was _ Papyrus…

Sans had to shake the thought away.

He reminded himself with a bitter pang that it was public knowledge what a nuisance he was to his brother. The fact that the shifter knew about it and brought it up shouldn’t surprise him as much as it did. Not when he had even the subtle twitches of Papyrus’s face down to an eerily uncomfortable science.

Still, there was something to be said for a monster that knew someone else’s weak points so intimately. He wanted to cower, to hide away. He couldn’t look the monster in the eye—too afraid to see disappointment in his brother’s face.

A hard shiver ran through Sans’ body, the pudding slowly taking full effect. Yet again he wished the drug did more than just shoot up his arousal, wished it would at least dull his other feelings in return so he wouldn’t be pent-up from so many disorienting mixes of emotions. He’d rather feel nothing at all than both want to be fucked and hate every minute of it.

In this case, it might’ve been best if the pudding just knocked him out completely.

The monster didn’t react to his body’s shaking save for giving Sans a stern frown that seemed plucked straight from his memories of Papyrus’s lectures, “Do you have any idea how much  _ money _ I’ve spent on rescuing you? And from situations you could’ve  _ easily _ avoided?”

He had  _ some _ idea.

The guilt was overwhelming.

Papyrus deserved better. Papyrus deserved the best things this shitty world had to offer.

Sans was not one of those things.

Not-Papyrus shifted his weight back at last, even deigning to let go of Sans’ wrists, but Sans made no attempt at retaliation with his newfound freedom. He couldn’t. Not now when the pudding had made his cunt form in a surge of magical arousal, already slick and wet and ready. It was all he could do to keep his legs together, hot tears spilling down over his face as the monster pretending to be his brother took a long, lingering look over his form.

It was gross.

It was nauseating.

He didn’t want to see the way Papyrus’s sockets half-lidded with lust. Didn’t want to see his baby brother’s gaze focused on his exposed pelvis with a hunger he’d never seen in them before. Like it was taking everything he had not to fuck Sans right then and there.

He  _ hated _ it.

He hated it even more that, when the shifter lifted up his shirt this time and brushed Papyrus’s hands against his ribs, his body tingled with welcome anticipation.

He should’ve had the whole cup.

Maybe that way he would’ve overdosed into sweet, blissful oblivion.

The Papyrus copy moved in, pressed his brother’s mouth to the side of his skull as he hissed, “With the amount of gold I’ve sunk into your well-being, I should be able to have you whenever I like.”

The words felt like ice water being poured into his soul.

Papyrus wouldn’t say that, he reminded himself.

Papyrus  _ wouldn’t say that _ .

But it didn’t make a difference what Papyrus would and would not say when the monster wearing his face was scorching the words into Sans’ mind for an eternity.

“D-don’t do this.” He was back to begging, desperate and fearful, “Please d-don’t… please don’t do this to me.”

“What are you talking about, Sans?” Not-Papyrus said with a sigh.

Even  _ that _ was just like his brother. The sigh, the frown, the scrunch of his browbone, the inflection of his words— ‘What are you talking about, Sans? Of  _ course _ I know what I’m doing!’—every part was exactly as Papyrus would’ve said it. He could only wonder how long the shifter had watched his brother to perfect its imitation.

A sick, roiling feeling ripped through him at the knowledge that he’d likely learn more about his brother now than he’d ever wanted.

“W-why would you… why would… w-why do this?”

“Sans,” the Papyrus impersonation scolded, looking pointedly at the slick gathered at his pussy, “Don’t pretend that you don’t want this when you’re so wet already.”

_ You did this to me, you bastard _ , he wished he could shout,  _ I  _ **_don’t_ ** _ want this. I could  _ **_never_ ** _ want this. _

But all he could manage was a pathetic whimper, blubbering and teary.

The copy gave him a weary look before patting the side of his femurs as if to console him. Sans desired nothing more than to back away from the touch. Not that the shifter noticed or cared about his revulsion as it slowly changed from patting at his legs to smoothly stroking both his femurs easily up and down.

“You look good like this, brother,” the monster continued, murmuring lowly, “All dripping and eager for me.”

The words made him instinctively recoil, body shuddering, “D-don’t… don’t touch me. Don’t t-touch me.”

The copy ignored him, instead moving to peel off the gloves from his brother’s hands. “Tell me the truth, Sans. How long have you wanted me to fuck you?”

The sickening lurch the words provoked in him kept Sans from speaking.

It didn’t matter—the monster went on, unhindered by his silence, “Is that why you kept getting kidnapped?”

With the gloves folded and placed carefully to the side, the monster rubbed the bare bones of Papyrus’s hands against Sans’ thighs, all the way up to his hips. Sans shivered at the touch, his internal disgust battling against the shot of arousal the pudding forced through his system. Papyrus’s hands travelled further up still, toying with the zipper of Sans’ jacket before reaching up and pulling at it by the shoulders. The fur of his hood tickled against his face as the monster adjusted it till he could easily snake it off of him.

Once off, that too was meticulously folded and set down, neat and orderly, as the monster imitated his brother.

“Were you waiting for someone to put you in your place? To fuck you like a whore till you were gagged and filled with cum?”

He continued speaking but Sans didn’t say a word. He couldn’t, grinding down his teeth the way he was to keep from making any sound at all; to keep from vomiting at the imagery every sentence sparked in his mind’s eye. It was difficult, not in the least because the copy had both Papyrus’s hands underneath his shirt now, stroking lightly along his ribs, playful and teasing. It was unnerving to feel bone against bone like that, hands that weren’t his own touching him in a way that even he’d never bothered to.

“Were you hoping I’d get mad enough to do it myself?” Not-Papyrus rumbled the words with dangerous promise, hands scraping roughly back down along Sans’ spine, sharp points catching in the notches along his body and making him hiss.

Still, Sans didn’t answer him.

Maybe if he just lay there like the tuna he was advertised as, the shifter would get bored with him and leave.

“Well.” The hands retreated and it was only the clink of a belt being undone that let Sans know where they’d gone, “You certainly got what you wanted, didn’t you brother?”

He looked up and felt his soul nearly stop dead in his chest.

The monster had worked open Papyrus’s pants and was now lightly thumbing at the head of his erection.

It shouldn’t have been surprising—he’d expected as much, after all—but, somehow, actually seeing it was different from having guessed at what would happen. If he’d had the presence of mind, he might’ve noted the length of it or the thickness or the way the magical construct was just a shade slightly darker than his own red. As it was, all he could comprehend was that it was actually happening; that this freak of a client was going to put that inside of him.

That it was going to fuck him with his brother’s cock.

“N-no. No… no, oh g-god, no,” Sans scrambled backwards, bunching up the sheets under his feet as he pushed at the mattress in an effort to get away, “F-fuck, don’t. Don’t t-touch me, d-don’t come  _ near _ me!”

Papyrus’s mouth only curved up into a smile, bemused.

The monster stalked forwards, stroking leisurely at Papyrus’s dick. Sans’ back hit the headboard. There was nowhere for him to go. He darted his gaze around, searching for an escape while still stuck in a confused loop of angry curses and desperate pleas. None of them mattered. The shifter continued towards him, reaching out with Papyrus’s unoccupied hand to grab at his ankle.

With a firm tug, he pulled Sans down onto his back again. Even as he shouted and squirmed and tried to push away, the shifter grabbed onto each of his femurs tightly, spreading his legs wide and putting his dripping cunt on full display. It lined them up so that the head of Papyrus’s cock was just the barest inch away from him.

“S-stop! Stop, stop, d-don’t—!”

Sans choked on his words as the monster slammed into him.

“ _ Ohh _ ,” the copy moaned with Papyrus’s voice, and Sans didn’t think he’d ever be able to unhear just the way it sounded, echoing as it was around the inside of his skull, “ _ Fuck _ , that’s good.”

It was big. Even with the pudding making him wet, it stretched him almost to the point of pain. Sans tried to focus on that; tried to focus on the ache of his walls instead of the fact that he was being filled up with—

_ Don’t think about it. _

_ Do  _ **_not_ ** _ think about it. _

Still, the tears formed at his sockets.

Still, it felt like his soul was being crushed with the weight of what was happening.

“Do you feel that, brother?” the copy whispered, reverent and low and with the familiar familial address that just made Sans flinch all the harder, “Do you feel how tight your pussy is around my cock? It’s like you were made for me.”

The monster slowly pulled part-way out of him, the space Papyrus’s cock left making him feel sickeningly empty. It paused for a moment before rushing back in, just as hard as the first time and somehow even deeper. Sans could feel it sting inside him. The imposter repeated the motion. Again and again and again till it sped into proper thrusting and Sans felt his brother’s erection throb within the confines of his cunt.

The horror of it seemed to crash down on him all at once.

Sans let out a broken wail of despair.

“G-god, no… s-sto… p… s-stop, I ca… n’t take it… I can’t t-take any… more, ple-ease…”

“Shh,” Not-Papyrus—because that was the one point he desperately needed to latch onto to keep him sane; that this was  _ not _ his brother,  _ not Papyrus _ , because slipping into any other thought for even a  _ moment _ would destroy him—soothed, rubbing a careful hand along the top of his ilium in a manner gentler than Sans could ever remember his brother being with him, “Was I too fast for you, Sans? I suppose, in my haste, I forgot to consider how delicate you are.”

The shifter pulled out and Sans felt his pussy clench, bereft of the girth of Papyrus’s dick.

“Just let the Great Papyrus assist you with this, brother.”

Sans was going to throw up.

The monster rubbed the full length of Papyrus’s cock against the folds of his cunt, the wetness allowing him to slip easily back and forth. Sans tensed at the teasing, gripping tight onto the bedsheets even as the tears continued to stream down his face. The copy dragged his cock upwards till it pressed against his clit. He circled the head around it, building a rising intensity with each grazing pass over the nub of magic. Then, the monster let the weight of the erection lay there for a moment against it and Sans’ felt his cunt throb in anticipation. With a chuckle, the monster pressed a thumb down against the head of Papyrus’s cock and let the phalange slide down to stroke at Sans’s clit, smearing it with pre-come.

“Ahh… ah, ahn…” Sans couldn’t hold it back anymore. The drug in his system made every touch burn in the most pleasant way, made him want and need and desperate to come. It wasn’t enough to take his fear or his repulsion away, but it was more than plenty for overcoming his urge to stay silent.

“Enjoying yourself?” the shifter asked, Papyrus’s voice playful and sultry.

There was only one answer to that and Sans gave it in the form of another choked off cry.

“It’s okay to like it, brother.”

It wasn’t.

It definitely, absolutely, was  _ not _ .

And Sans hated that he did.

The monster shifted a little, held Sans more firmly as it re-positioned Papyrus’s cock at his cunt. Sans braced himself but the copy only dipped in shallowly with the head. Slowly, carefully, it repeated the motion, dipping in and out of his folds. It lingered in a few of the pseudo-thrusts, swirling the head around the inside edges of his pussy, rubbing firmly against the walls. Sans shivered every time, the action only making the tension inside him go tighter and tighter.

It changed tactics again, pulling out and rubbing the dampened head against the outside of his pussy once before circling it back towards his clit. There the monster began to rub, firm and with purpose, using Sans’ own slick gathered onto Papyrus’s cock to ease the way as it dragged the full length of the erection against his small bundle of magic.

“O-ohh… mnn, a-ah… hah…”

He was starting to pant and drool, eyelights threatening to roll up into the back of his skull.

“That’s right, Sans. Let me hear you.”

His body was going tense, locking up all rigid.

“Ah-ah… hahh…  _ nn _ …”

“You’re close, aren’t you?” the monster said, and without waiting for an answer, it increased the pace, shifting Papyrus’s hips up at the same time to better the angle. It rocked against Sans, rubbing and pressing the magic around and over his clit again and again till it hit the perfect amount of pressure at just the right place.

The sensation of release ran through him.

Automatically, the feeling prompted Sans to announce himself like he’d been taught to. “I’m… I-I’m gonna—I’m co— _ uuhming! _ ”

Long, tapered phalanges stroked him through his release, keeping the aftershocks going till he felt well and truly sated. But as the haze of orgasm disappeared, so did the numbness of his mind. He was dimly aware of something being whispered to him, low and encouraging, but he couldn’t hear it over the deafening buzz of his own utter humiliation and disgust.

He came.

A client took his little brother’s form and rubbed Sans off with an imitation of his dick

and

he

_ came _ .

Sans let himself go motionless, still and silent as he stared up at the ceiling.

He really was the worst.

“Now it’s my turn,” came the copy’s voice of his brother and still Sans couldn’t find it in himself to move or to say a single thing.

“Since I’ve done so much for you already, you’ll have to do a little something for me.” The shifter leaned fully over his body then, dipped down just far enough to press a chaste kiss to the front of his mouth, nuzzling against him afterwards in a way Papyrus hadn’t done since they were kids, “Call me ‘Boss’, Sans.”

He wouldn’t.

He wouldn’t say or do anything at all.

Let the monster have him. How much worse could this get?

“Brother, are you listening?”

It’s not like he could hate himself any more than he already did.

“ _ Sans _ .” The imposter was starting to sound impatient, voice reminiscent of the tone Papyrus took on every morning he tried to wake Sans up.

If only he could curl up and go to sleep right now.

Maybe, if he was lucky, he’d never wake up again.

“Call me ‘Boss’ or this is going in your mouth next.” It commanded, timbre hard and unforgiving, as if  _ that _ would make a difference.

What did it matter? Either way he was already filthy.

Either way he’d never be able to look his brother in the face again.

“ _ Do it, Sans. _ ”

But suddenly, the voice was all wrong.

It had gone back to being high-pitched.

Sans cautiously looked up at the unforeseen switch to see Papyrus’s face looking grim and foreboding. “Do it. Or I’ll tell your brother you  _ begged _ me to turn into him.”

Sans froze.

He stared at the shifter, soul kicking up into a frantic pace in light of his panic, leaving all his bitter apathy aside.

“You… you can’t do that.”

“Are you so sure about that?” A cruel, creeping smile spread wide across Papyrus’s face, “You know what? Better yet, I’ll tell him the  _ truth _ . I’ll tell him that you came just from me grinding his dick against your dirty little pussy.”

Sans felt dizzy, like all the feelings he’d been desperately suppressing were hitting him all at once. “How would… he… h-he’d never believe you.”

“With a brother that constantly disappoints him like you do, I’m sure this wouldn’t be  _ too _ much of a stretch. And if he’s a little difficult to convince then, well,” A laugh, and suddenly Sans was hearing his own voice speaking aloud to him, “I could always work my magic and let  _ you _ do the talking, if you catch my drift.”

Sans hadn’t thought it was possible for him to feel any lower than he already did.

He’d been wrong.

He scrambled up to his knees, resisted the urge to lay himself out prostrate as he begged, “No…! N-no, please, don’t—don’t tell him. Please don’t tell him, I-I… I’ll do w-whatever you say.”

There was a lengthy pause where the monster considered him.

Sans felt every second pass like the worst imaginable sort of torture.

“Good,” the copy finally said, letting its voice change back into Papyrus’s low growl, “Now go on and call me ‘Boss’.”

Sans didn’t feel any better for having convinced him. “O-okay, Boss.”

“Beg me to fuck you.”

“P-please fuck me.”

“‘Boss’.”

Sans swallowed down his nausea. “… Boss…”

“Do  _ not _ toy with me, Sans,” the Papyrus copy demanded, voice laced with warning, “ _ Say the whole thing. _ ”

“… please… f-fuh…” He couldn’t stop the tears flowing down his face, couldn’t stop the way his voice trembled and shook with shame as he spoke, “… p-please fuck m-me… Boss…”

“That’s better.”

The copy grabbed him by the shoulders and laid him back down. This time around, he didn’t wait even a moment before tossing Sans’ legs up over his shoulders and getting himself ready. He stroked himself back up to full hardness, rubbed his length tentatively against the lips of Sans’ pussy making him flinch, still sensitive from his orgasm.

“I want you to be vocal. I want you to end every fucking sentence with ‘Boss’ if it comes down to it.” Papyrus’s face swam in his vision through his tears, but Sans nodded along mutely anyways, “If you don’t follow through, a certain skeleton in Snowdin is going to learn some  _ very _ interesting things about his trashbag of a brother. Am I clear, Sans?”

“Y-yes… Boss.”

“That’s good, brother.”

Without any further preamble, Papyrus pushed into him, full and thick and filling him up to the brim. His fear made him tense, made him clench around the cock inside of him. The feeling only made his assailant moan aloud.

“Does that feel good?” he grunted as he tightened his grip on Sans’ legs.

_ No no no. _

“Yes… B-boss.”

“And?”

“A-and… i-it’s really—y-you’re really b-big.”

Papyrus sighed out loud at that, rocking his hips slowly back and forth. “You wanted this too, didn’t you, brother?”

He’d asked for this.

He’d asked his brother to fuck him.

He’d asked he’d asked he’d asked he’d asked—

“Y… yeah… B-boss,” Sans managed to force out, feeling his chest go tight like his body couldn’t restrain the feelings he buried in between his ribs.

Papyrus thrusted into him harder. “I bet you used to touch yourself while thinking about me. I bet you would fuck yourself on your fingers and wish it was my cock instead. I bet that you wished that I was there to fill you up with my cum.”

God god god he’d  _ agreed _ to do this.

He was scum, he was dirt, he was the lowest of the low.

“Y-yeah, Boss.”

“I bet you’d let me fuck you in front of everyone and stake my claim.” Papyrus picked up the pace, his movements faster and faster with each push till Sans felt constantly full, filled up entirely to his deepest, “You’d just lie back and take it like a whore, wouldn’t you, Sans?”

“I… I-I… would… B-boss.”

“Mmm, that’s good, Sans,” he praised and, despite himself, Sans shivered at the genuine praise spilling out from between his brother’s teeth, “Don’t hold back.”

Papyrus continued rutting against him and the motions went from uncomfortable to something a lot more pleasant. Sans could feel his body start to prepare once more, slicking the way even further as it readied to take another orgasm. His pussy gripped tight around the cock inside of him, hugging it in a way that made every thrust feel that much harder. He could hear Papyrus groaning above him, panting and cursing under his breath.

“Ah-ah-hahh… nn!” Sans moaned at the friction, every upward motion hitting him just right.

His brother leaned further over him and Sans squeezed his eyes shut, not wanting to see his face any nearer. His action was followed by low laughter as Papyrus continued to fuck into him and Sans felt his face grow hot with embarrassment. His brother was close to coming now, he could tell by the way his hips were starting to stutter in their rhythm.

Just a little more and it’d finally,  _ finally _ be over.

A hand stroked his face softly. “I love you, brother.”

Sans eyes shot open.

“I… w-wh…” The tears starting spilling over his cheekbones in earnest, “N-no. No. H-how could y…”

The thrusting sped up, making him sob all the harder. “ _ Nnn _ , that’s it. Come on.”

“Sto…p… stop, stop… n-no more… no more, p-please.”

“Ahh,  _ fuck _ , that’s so good, brother,” Papyrus panted, and Sans could feel his cock throbbing with the need to release, “You’re clenching around me, Sans. Ask me to let you come. Remember what you’re doing this for.”

Sans choked back another desperate wail for mercy, tried to force himself to use the words he needed to instead, “I-I want… I w-want to…”

Die. I want to die.

I want to die I want to die I want to die die  _ die _ .

“What do you want, Sans?” Papyrus prompted him again, relentlessly rutting against him now, his hips smacking up against Sans till the sounds of it filled the room. Sans felt the tension in his body ramp up once more, his soul twisting in a sickening way.

“P-please,” he whimpered, not sure what he was begging for at this point.

“Say it.”

“L-let me come.”

“‘Boss.’”

“… B-boss…”

“ _ Sans _ .” His tone was not negotiable.

The pressure was building inside of him, rising higher and higher. It pressed against every single one of his bones, torturous in its intensity.

Papyrus rammed into him hard enough to make him scream, more tears springing up in his sockets from the strain. “ _ Say it. _ ”

“Ahh… ahn, I… let…” He couldn’t hold it back anymore. Not with the way he could feel every thrust so deep inside him, rubbing against his walls. He couldn’t take it, “L-let me c-come, b… let me come, B-boss… p-please.”

“You may.” Papyrus smirked.

And with a few more well-aimed thrusts, Sans felt the tension in his body finally snap and he turned his head to the side

and

threw up.

Sans was hardly aware of the rocking against his hips dying down to a stop.

He had a hand thrown over his midsection, clenching weakly at his shirt as excess magic expelled from within him. With every heave, he felt more and more light-headed but he couldn’t stop until there was no more left to give. He made piteous groans as his body emptied itself, hacking and coughing when it finally seemed at an end.

He felt weak.

He couldn’t even lift a hand to clean off the bits of vomit still clinging to the sides of his mouth.  

“Well.  _ That’s _ a bummer.” The voice was all wrong again and Sans shakily turned back to face the monster, noting that it had pulled out of him though it was evidently still hard, “I don’t think your brother’s the type to be into that.”

Sans was quiet, staring at the monster with more clarity than he’d had since the start of all this.

“But that’s alright,” it continued brightly, “I  _ did _ have one other choice. And I think it’s plausible that he might take an, uh… shall we say,  _ ‘scientific interest’ _ in this sort of thing.”

Right before his eyes, the monster shifted till Sans was looking at a very familiar dark coat and a face he hadn’t seen in ages. He felt cold all over. Bones rattling at the sight.

Gaster gave him a crooked grin. “Would you say that you’re a bit of a daddy’s boy, Sans?”

“Get off the bed and stand up, please.”

Muffet. Muffet was here. Sans’ head snapped up. She was flanked by two large guards. The client had gotten off the bed and was standing next to it. Muffet looked at Sans and for the first time since Sans had met her, there was something like true remorse in her eyes.

She didn’t say a word, instead nodding at the guards who walked up and grabbed the client under each arm. Sans could hear it break out into protests but Muffet didn’t even look its way as the guards dragged it forcibly from the room. Instead, she watched Sans quietly. Once it was just the two of them in the room, she sat down carefully beside him on the bed.

“Sweetie…” She started, and instinctively flinched at the pity laced in her words.

Sans hated Muffet. He  _ hated _ her.

He wanted to shout. He wanted to scream. He wanted to fucking  _ hit _ something because this was  _ all her fucking fault _ .

But.

He was just so, so,  _ tired _ .

So, when Muffet wrapped her many spindly arms around him and began stroking at his back, Sans simply leaned into her and started to cry.

 

 

 

He wasn’t taking any visitors but the human found him anyway.

It wasn’t like it was hard—he hadn’t left the dark confines of his room in days. Muffet had monsters checking in on him around the clock, concerned that he would try to hurt himself, especially since he’d been skipping multiple meals. Sans wanted to laugh at her.

If he knew how to kill himself with all the safeguards she had in place, he’d have done it already.

As it was, all he could do was lay in bed and think about how disgusting he felt.

“Sans…?” the child called out to him.

He didn’t respond.

He wanted them gone.

He wanted everything that reminded him that there was a world outside this room to stay out and never come back.

He wished that they would all just leave him alone.

Leave him alone to sleep and sleep till he never woke up again.

Frisk moved up closer to him. “Was it… was it really bad this time?”

No way he could tell a kid about something like that, even if he’d felt inclined to in the first place.

Besides, what would he even say? That he’d gotten fucked by a monster wearing his brother’s body? That every time he closed his eyes, all he could see was the look on Papyrus’s face as he slammed into his cunt? That all he could hear were the sounds of his groans? That no matter how many times Woshua cleaned him, he could still feel his brother’s cock penetrating him through the wetness of his cunt?

No.

A child had no business being exposed to that.

The human put a careful hand on his arm before quickly drawing it back, as if afraid to frighten him, “It’s not… good for you to stay all alone like this. You should go out and talk to your friends. Leave your room and eat something a-and… take care of yourself.”

He didn’t bother responding to tell them just how incredibly unappealing all of that sounded.

“I think…” Frisk hesitated, and although Sans wasn’t looking at them, he could imagine the exact look of reluctance on their face, “I really think you should tell your brother, Sans.”

That was the absolute last thing he would ever do.

He wasn’t telling  _ anyone _ that, least of all his brother.

If the world had any mercy in it at all, Sans would never see Papyrus again.

He would quietly fade from his brother’s life and things would be better for it.

“He… he wants to help.”

No one could help.

Unless they were willing to dust him, no one could do anything.

“He cares about you. You know that, right?”

He shouldn’t.

He  _ wouldn’t _ —not if he found out about this.

“Sans…” The human sounded desperate, “Sans, Papyrus loves you.”

Like a dam breaking inside of him, Sans laughed.

Sans laughed and laughed and laughed till his body was shaking and Frisk was taking several steps back away from him. He could see them tremble and it only made him laugh harder, pain racking up along his ribs and lancing through his soul. Their mouth was moving, they were trying to speak to him, but he couldn’t hear anything over the sound of his own rancorous laughter.

He laughed and laughed till he was screaming and sobbing and thrashing in bed.

By the time Muffet came in with guards to hold him down, the human was already gone.

 

<<<<<<<<<<

 

He wasn’t taking any visitors but the human found him anyway.

It wasn’t like it was hard—he hadn’t left the dark confines of his room in days. Muffet had monsters checking in on him around the clock, concerned that he would try to hurt himself, especially since he’d been skipping multiple meals. Sans wanted to laugh at her.

If he knew how to kill himself with all the safeguards she had in place, he’d have done it already.

As it was, all he could do was lay in bed and think about how disgusting he felt.

“Tell me what you need and I’ll fix it, Sans.”

The determined way they said it ripped a bitter laugh from the haze of his apathy, “No one can fix this, kid.”

“What happened—” They seemed to think better of what they were asking, “What… what would’ve made it better?”

“Nothing,” Sans spat, and his voice came hoarse from disuse and stale anger, “Nothing would’ve made it better. The fucker had a friend in the guards. The only thing that even stopped it this time was that Muffet finally saw what was happening and came in to put an end—”

Frisk wrapped their arms tight around him.

Sans was shocked into silence, arms dangling uselessly at his sides as the child hugged him close.

“Leave it to me.” They whispered, full of promise.

 

<<<<<<<<<<

 

One hand clamped over Sans’ mouth and pegged his head against the wall. Another hand held up a cup of the drug. The monster tipped it into Sans’ eye socket. Sans screamed into the hand and thrashed his limbs. But by the time the monster let him go, he could feel the substance making its sluggish journey inside him.

Sans curled into a ball.

“Oh god. Oh my god. Oh my god.”

The monster pet Sans’ back.

“There’s no need to be so difficult. You’re going to enjoy it, of course.”

“Get off the bed and stand up, please.”

Muffet. Muffet was here.

 

**Author's Note:**

> well at least it ends on a positive note?? B'D
> 
> ............. unless you read the original fic. then u know that things are only gonna get worse before they get worse-er //shakes fist at germ
> 
>  
> 
> ~~i finally got to use the "meant to be read by absolute monstrous garbage only" tag ahhhh i feel so accomplished~~


End file.
